Physicist Garrett Lisi, executive editor of Scientific American Mariette DiChristina, and cosmologist Stephon Alexander, pose with Simon Field

We all arrived at about 5:30 Friday afternoon, and as we were waiting for dinner, I found Max Tegmark talking to Paul Davies, and I asked a question that had bothered me on the drive over. How do gravitons get out of a black hole?

Paul Davies jumped right in. “That’s easy,” he said, and launched into a 20 minute description of virtual particles, event horizons, and evaporation of black holes as negative energy fell into them. It turns out he had written the first paper on this subject 20 years ago or more. I think I followed his descriptions pretty well (he is very good at explaining things to non physicists), but I will have to look up that paper before I try to explain it to anyone else. I left him with Lawrence Krauss and went to dinner.

At dinner I found myself across from Saul Perlmutter, the cosmologist who discovered the accelerating expansion of the universe, that led to the realization that dark energy accounts for 74% of everything in the universe. I brought my friend Theo Gray over to meet him, and explained that I had just seen Saul, Max, and Garrett Lisi on television the night before, explaining cosmology to Morgan Freeman.

Me posing next to Saul Perlmutter

On Saturday, the actual talks in conference rooms started. I chose to start with Nat Torkington’s lightning talks, where speakers get five minutes to describe what they have been working on. These are always fascinating, and a great way to get to know who you absolutely must talk to later. I happened to sit next to physicist Alan Guth, the guy who figured out there was a period of inflation right after the big bang. I told him about my talk with Paul Davies, and he said it was probably best that I talked to Paul first, as Alan might not have had a ready answer for my question. I’m really going to have to read that paper.

The talks were great, everything from getting sued by Facebook for using what they had published on the web, to worm spit used to make biocompatible LED tattoos, to Josh Bailey’s irresponsible behavior with high voltage, to Beth Shapiro’s wonderfully funny experiences in Beringia digging up fossil DNA and eating mammoth meat.

After the lightning talks, Michael Shermer and Bruce Hood gave a great talk about belief and reason. Then came lunch, where I sat with Jose Gomez-Marquez and talked about using some of the techniques I used to build scientific toys to build medical devices for third world countries. I left him with some of my tiny microscopes to make a laser projection nebulizer analysis tool.

After lunch Paul Davies led a discussion on how to find evidence that life on earth was created more than once from basic chemicals. Finding that life evolved more than once on earth would make it more likely that it evolved elsewhere as well.

Later, Lee Smolin talked about how loop quantum gravity theory got started, Garrett Lisi talked about developing a theory of everything while surfing in Hawaii, Stephon Alexander talked about expanding Alan Guth’s inflation theory to explain unanswered questions, and all of these stories were told through personal experiences and humor, and you got a real sense of what it is like to live on the cutting edge of theoretical physics.

On Sunday, I taught Connor Gray how to demonstrate science toys while his father Theo and I went to more talks. In return for doing that, I gave him a 405 nanometer laser (purple light). He had spent the day playing at my farm the day before, and had gotten the same 5 hours of sleep that we all had, but he did a stellar job at the demonstrations. Watching Devin and Michael Shermer breath fog out of their noses like dragons after eating whipped cream frozen in liquid nitrogen was a real treat.

Danny Hillis, Simon Field, Paul Fenwick, and Stewart_Brand at SciFoo10

Paul Fenwick getting charged up

Simon Field posing with Lee Smolin at SciFoo10

]]> http://sci-toys.com/sciblog/archives/237/feed 1 http://sci-toys.com/sciblog/archives/228 http://sci-toys.com/sciblog/archives/228#comments Thu, 25 Mar 2010 21:57:31 +0000 Simon Quellen Field http://sci-toys.com/sciblog/?p=228

Self-Igniting Dragon Fart Powder

Kinetic MicroScience, the people who gave you the Gauss Rifle, the Plastic Hydrogen Bomb, the Three-Penny Radio, the World’s Simplest Steamboat, and many, many more fascinating science toys, have announced a new product, to come out on the beginning of next month.

Self-Igniting Dragon Fart Powder will certainly be a best seller.  Just follow the simple instructions for hours of fun.

Full artwork for the product packaging can be seen here.  The back label contains instructions, applicable warnings and usage information, and other useful and important items.

Unshielded Twisted Pair Cable

Sometimes a simple piece of technology is so ingenious, it makes you wish you could meet the genius that came up with that idea. Simple twisted pair wiring is just that kind of idea.

Long wires work great as antennas, picking up all kinds of static and noise from their environment.  That is bad for communications, where you only want the signal from the source to get to the receiver, without all the environmental noise.

The clever trick is to use something called differential mode transmission.  You send your signal on one wire, and you send an inverted copy of the signal on a second wire that is right next to the first one.  At the receiver, you invert one of the signals, and then add the two together.

Any noise that is picked up by the pair of wires will be inverted in one of the wires, so that when the signals are added, the noise from one wire will exactly cancel the noise from the other wire, leaving no noise at all.  In contrast, adding the two signals will double the strength of the communication you care about.

In one trick, we reduce the noise to zero, and double the signal, giving us the high “signal to noise ratio” that is the holy grail of communications engineers.

Of course, if we have a bundle of wires all carrying different signals, some of them will be closer to one wire in the pair than to another, and we get a form of noise called “crosstalk”.  But twisting the pairs eliminates that, because in a short distance, any signal induced by one wire in the pair is cancelled by the second wire, which the twist has brought closer to the other pair.

Just twisting isn’t quite enough, however, since if all the pairs had the same number of twists per inch, there would still be some correlation in the signals, and some crosstalk.  But if you look closely at the photo above, you will see that each pair has a different number of twists per inch.

A side benefit from differential mode transmission is that it radiates less energy in the form of radio waves into space.  The nearby opposite signals absorb one another, so less power is needed to send a signal the same distance in the cable, and less interference is transmitted to other cables.

So who was the genius who came up with this idea?  Did he get fabulously wealthy?

As with many of these stories, the answer is that this stunningly brilliant idea didn’t occur to someone all at once, but took many iterations over many years to take form.

Telegraph lines and early telephone lines used a single wire to send the signal.  The earth was used instead of a second wire.  The circuit did not actually return to the battery through the earth, there would be far too much resistance.  Instead, the earth, being a big object with lots of electrons, can simply absorb or emit as many electrons as are required.

When electric trolley cars were installed next to the telegraph wires, the sparks and current changes from the trolleys acted as strong nearby noise sources, and interfered with the signals.  To get around this, telephone companies went to differential mode transmission, using two wires strung a couple feet apart on cross beams at the tops of poles.

This worked pretty well for trolley car interference, but as electrical power lines were installed carrying alternating current, a new source of interference came along.  This was especially troublesome because the electrical wires were strung using the same poles as the telephone wires.

To get around this problem, the telephone wires were crossed every few poles.  The power line interference was low frequency, so it had very long wavelengths.  Crossing the phone wires every few poles had the same effect as a twisted pair for eliminating low frequency noise.

When telephone wires were bundled together, however, the noise was not just the low frequency power line noise, but higher frequency noise from the other phone signals.  At this point, it made sense to twist the wires together a few times per inch instead of a few times per mile.

So now we have our familiar computer network cables, handling gigabits of information per second, all thanks to a bunch of telephone engineers solving one little problem after another.

I still hope someone got fabulously rich.

H. bacteriophora escaping a dead insect pest

Heterorhabditis bacteriophora is a nematode.  A simple roundworm.  Colorless, unsegmented, with no appendages, it eats bacteria.

So why do they make great biological insecticides?

They are farmers.  They have a symbiotic relationship with the bacteria that they eat.  The bacteria like to live inside insect hosts, which they kill and eat.  The nematodes eat the bacteria, and then when the insect is eaten up, the nematodes carry some of the bacteria to a new insect.  They then regurgitate the bacteria inside the insect, to seed their bacteria farm.

The nematodes are harmless to plants and mammals, but quite deadly to many soil insect pests.  They target dozens of harmful pests, yet have no effect on bees and other beneficial pollinators.

Because they are microscopic metazoans, they can be mixed with water and sprayed using common pesticide equipment.  They can be grown in standard fermentation tanks up to 40,000 gallons.

The bacterial symbiotes are Photorhabdus luminescens. They kill the host insect quickly, in one to two days.  They need the nematode in order to enter the host insect, and the nematode can carry them much longer distances than they could travel alone.  In return, the bacteria provide an environment in the host insect that the nematode needs for survival and reproduction.  The bacteria produce immune suppressing proteins that prevent the insect from killing off the nematodes, and they produce anti-microbial molecules that prevent other bacteria from colonizing the dead insect.

As biological controls, the nematodes have some advantages over chemical pesticides.  They aren’t toxic to mammals, and they don’t pollute the ground water, and they target only specific pests.  On the downside, they are living creatures, and are harmed by drying out, ultraviolet light or heat, and they can’t be stored for long periods.

Another plus for the worms is that you can tell if an insect was killed by them.  The bacteria glow (hence the name luminescens).

When mutations cause genes to stop functioning, the effect can be caused by damage to the gene, or by damage to the genes that turn on the gene that is no longer expressed.

Take the example of hen’s teeth. Although chickens lost the ability to grow teeth 60 to 100 million years ago, the mechanisms for supporting the growth of teeth are still intact, and can be induced to grow teeth by replacing one lost protein, called BMP4, or reintroducing the production of that protein by the neural crest cells.

There are many genes involved in making teeth, and it appears that in birds, interruption of a single pathway is responsible for the loss of teeth. The rest of the mechanisms are still preserved, 60 million years later.

A similar genetic accident may be responsible for cats being carnivorous. Cats, from domestic cats to tigers and cheetahs, seem to have lost one tiny gene that is responsible for the sweet receptor in taste buds. They can’t taste sugar. They can’t taste the sweetness of plant materials like fruits or sweet sap.

This has importance in designing cat food, but it also gives insight into carnivore evolution and taste.

So, while a hen may still have a sweet tooth, even though it has no teeth, a toothy kitty has no taste for candy.

Our farm gets its power from traditional silicon solar panels. But I have long been interested in the idea of using tiny antennas that resonate at light frequencies to collect solar power using what are called rectennas. A rectenna is an antenna connected to a diode that “rectifies” alternating current into direct current.

Making antennas half the size of a wavelength of light is a nanotechnology challenge, but several designs have been fabricated and tested in laboratories. The main reason for the excitement is that such a system can, in theory, reach efficiencies of 85%, compared to silicon efficiencies below 30%.

One of the main problems in nanotechnology is building those tiny things. Especially in the huge numbers needed to coat a big solar panel. But new techniques in making tiny shapes out of DNA may come to the rescue. Paul Rothemund has been making things out of DNA for years, working on building computers out of DNA to solve difficult problems in computation.

Researchers have already made DNA conductive like a metal, and made metallic arrays using DNA scaffolding. They have used ink-jet printers to paint surfaces with DNA. It seems to me that building tiny antennas and the low pass filters and MIM diodes needed for an optical rectenna is possible using DNA to form the parts, and coat them in regular arrays over large surfaces.

The DNA would self-assemble the antennas into large thin-film crystals to convert sunlight into electricity.

I am not a commodoties trader, but I buy the metal indium in large quantities, and process it into liquid metal alloys and alloys that melt in hot water.

I used to buy indium for about $50 per pound. Now it costs ten times that.

Indium is about three times more abundant in the earth’s crust than silver or mercury, although some sources claim it is about the same as silver. So why has the cost of indium gone from much less than silver to much more than silver?

Big screen televisions.

Big screen displays need to have an electrically conductive coating on the glass that is transparent. Tin oxide can be used, but it is not as conductive as indium tin oxide. That 60 inch big screen TV is coated in indium tin oxide. So is the display in your laptop computer, your cell phone, and your personal digital assistant. And indium tin oxide is 90% indium oxide, and only 10% tin oxide.

Indium is also used in several semiconductors, in welding, and in nuclear control rods. But none of those industies has grown as fast as the number of flat screen displays, or the number of square miles of flat screen display produced since this century began.

And I do my part. The demand for a non-toxic liquid metal to substitute for mercury is surprisingly high, and I sell a lot of it these days. And since I buy indium in bulk, my customers get last year’s price, until I run out. Then I will have to swallow hard and write a big check for the next batch.

An email from a friend caused a chain of events that led me to a wonderful paper by Charles Kerfoot, about resurrecting fossil eggs from progressively deeper and older layers of sediment in a lake, and hatching the eggs from different layers to compare the creatures (Daphnia retrocurva) as they evolve over time.

As these eggs are covered in sediment, they remain dormant (in facultative diapause) for as long as 300 years or more (the paper only shows data going back to 1825).

In lakes that freeze over, sediments arrange in annual layers called varves. They can be counted like tree rings. In addition to counting the annual layers, the sediments were also dated by Cesium, Potassium, Radium, and Lead radio-dating, which confirmed the dates done by counting.

The eggs from different layers were hatched, and the Daphnia (water fleas) that grew from them show differences in the body armor over time as they adapted to evolving predators. Genetic analysis also shows evolution, both in mitochondrial DNA, and in allozyme analysis, where enzymes that differ only in their amino acid sequence show where specific mutations in a gene have ocurred.

By tracking the mutations as they accumulate in successive generations, further confirmation of the date sequences and evolutionary change becomes visible.

Other eggs and fossil remains show how the predators of Daphnia evolve to keep up with defensive adaptations by their prey.

By hatching dormant eggs from sediments laid down over hundreds of years, we can watch evolution progress right in front of our eyes, in a complex crustacean, not just in bacteria and viruses.

I live on a mountain.

I get my high speed Internet by using a microwave link from a tower on the hill near the house to the top of a tall building in San Jose, a distance of about 11 miles.

Since that link provides me with much more bandwidth than I actually use, even when streaming video from my henhouse, I give free Internet access to those of my neighbors who don’t have line-of-sight to San Jose. Some of the links are what we call “wires through the woods”, but several are WiFi links, using directional antennas and Linksys WRT54G wireless routers.

Our longest link is 2.89 miles, to a house across a canyon from me, on another ridge to the east. But just for fun, I set up a dish aiming at distant Fremont, and put another dish on the lumber rack of my pickup truck and drove to a hill above that city and parked on the side of the road, aimed my dish towards home, and got a solid signal at a distance of a little over 26 miles as the crow flies. I was getting a nominal 5.5 megabits per second at that distance, which allowed me to get actual measured throughput of just under 3 megabits per second. Surfing the web was still plenty fast enough, and what delay I was seeing was the normal server delay. I could not really tell any difference, subjectively, from surfing at home.

I would have gone farther, but I had run out of road.

Back home, I drove to the top of the mountain, and aimed my dish around at various parts of Silicon Valley and beyond, and used the NetStumbler program to find access points. At one point, I was able to get a signal from a transmitter in Oakland, about 45 miles away.

I was feeling pretty proud of myself, with my truck mounted 24 dBi microwave dish and my 300 milliwatt WiFi card in the laptop computer.

Then I read about some guys who went just under 125 miles using 300 milliwatt cards in their laptops, feeding 10 and 12 foot parabolic dishes — one towed on a trailer.

As I had found in my own experiments, the hard part is finding two places within line-of-sight of one another that are far enough away to make the project interesting. These guys set up one dish on a mountain in Nevada, and then drove into Utah.

To get farther than mountaintop to mountaintop, some Swedish folks put a WiFi unit in a balloon and sent it up to an altitude of over 18 miles, and received signals from it as far away as 195 miles away. They used a 6 watt amplifier, since a 12 foot parabolic dish is a little heavy for a weather balloon to lift, and somewhat hard to aim.

Years ago I used my amateur radio equipment to talk to astronauts in the Space Shuttle and International Space Station. There are amateur satellites in orbit that store and forward email to amateurs around the world. WiFi and satellites are already connected to provide Internet access to recreational vehicles. It seems to me it is only a matter of time before a low earth orbiting WiFi access point breaks all earthly records for distance.

The National Park Service estimates that two-thirds of Americans can’t see the Milky Way from their backyard because of light pollution. And 99% of the population lives in areas considered light polluted.

At the rate light pollution is increasing, by 2025 there will be no areas in the continental U.S. that are not affected.

Most of the light pollution is caused by wasting electricity. Street lights that aim their light up into the sky are wasting the energy used to make the light. By properly aiming it down where it is needed, money and energy are saved, and people can see the stars again.

Like other forms of pollution, bright city lights are causing harm to wildlife, such as migrating birds, sea turtles, and nocturnal animals such as California’s glossy snake. When darkness never falls, predators that hunt in twilight can hunt all night, and the adaptations nocturnal animals depend on are no longer effective. Nocturnal salamanders wait for dark to hunt, and get less food in brightly lit areas. Light affects hormones that tell frogs when to put on fat for egg laying, and fireflies don’t mate near incandescent lighting.

Astronomers have been complaining for a long time about light pollution.

We can fix light pollution and save money by doing it. People just need to pay attention to where the light is going. Aim low.

Cyclosporin is famous for its use in transplant surgery, where it suppresses the immune system to prevent rejection. It is made by the fungus Tolypocladium inflatum as a defensive weapon, as are many of our common antibiotics, such as penicillin.

As you can see, it gets its name from its chemical structure. It is made of eleven amino acids that form a closed loop. Short chains of amino acids are called peptides, and longer ones are called proteins.

Loops of amino acids (called cyclic peptides), have several features that make them especially interesting. Because they have no dangling ends for digestive enzymes to grab onto, they don’t degrade easily, and thus can be taken orally. They hold their shape better than non-cyclic peptides, making them more specific in their interactions, since they can’t deform to fit where they aren’t wanted (an important feature in biology). They can withstand higher temperatures and acidity, since they don’t break down as easily. Proteins usually denature when heated, changing their structure dramatically, as in egg white when it is cooked. Cyclic peptides and proteins are much more stable.

The stability of cyclic proteins can be further increased by linking the amino acids inside the loop together, forming ladder-like stuctures, webs, and knots.

The stability and specificity of cyclic proteins makes them especially useful to organisms, as they can remain active in many environments, are difficult for a pathogen to degrade, and can target their activity to reduce side effects.

One cyclic protein of interest is rhesus theta-defensin-1. It is a protein found in some primates which gives them a defense against HIV. Cyclic proteins have not yet been found in humans, but a genetic sequence similar to rhesus theta-defensin-1 has been found, with a small mutation (a premature stop codon) that prevents it from forming the full protein. Analyzing this sequence in a range of different primates shows that the mutation occurred seven to ten million years ago. If it had not been for this mutation, humans might have retained a defense against HIV to this day.

As budget cuts have limited some grand schemes for detecting Earth-like planets around distant stars, an new scheme to do it on the cheap has been proposed to NASA.

Called the New World Observer, the plan is to place a flower-shaped disk in front of the James Webb Space Telescope (the proposed successor to the Hubble Space Telescope). The 40 meter (131 foot) disk will be placed 30,000 kilometers (18,641 miles) in front of the telescope, to shield the telescope from the bright starlight, allowing the faint planets around it to be seen. The project is the brain-child of Webster Cash, director of the Center for Astrophysics and Space Astronomy in Colorado.

The strange shape of the disk, with flower-like petals on the edges, prevents diffracted light from reaching the telescope. The petals cause the diffracted light from the edges of the disk to destructively interfere with one another.

The star shade should allow the telescope to see planets around stars as far away as 35 light years from Earth.

The disk does not need to be made with extreme precision — a few millimeters here or there will not make much difference from 20 miles away. And the disk can be a few meters out of alignment and still block the light from the star. The cost of the project is thus small enough to qualify for one of NASA’s least expensive missions, the “Discovery-class”, which has a cost ceiling of $425 million.

But Webster Cash is not stopping there. His New World Imager proposal calls for two telescopes and two star shades, orbiting a thousand miles apart, forming an interferometer.

With such a telescope, he expects to be able to image features on the remote planets, such as oceans and continents, and search for “biomarkers” such as oxygen and ozone, that would indicate life exists on the planet.

Minik Rosing thinks he has found the oldest evidence of photosynthesis yet, in rocks 3.7 billion years old. He had already reported fossil plankton from that era in sedimentary rocks from Greenland and presented radiologic evidence of enrichment by living organisms in earlier papers.

He also thinks photosynthesis may be responsible for the creation of all the continents on earth.

Photosynthesis makes three times as much energy available for geochemical activity as all of the energy that comes from the molten interior. The new date for photosynthesis puts it in a time when there were no continents on earth. Continents are formed from granite, which is less dense than the basalt from which it is made, and on which it floats. Basalt is weathered into clays, and those clays form granite when they are melted.

The vast amounts of energy created by photosynthesis keep the atmosphere and the oceans out of balance with the minerals that make up the earth. This increases weathering, and changes the resulting products of weathering, favoring the formation of granite.

Granite is not found on any planets in the solar system except Earth. Could this be because only Earth has life?

My root beer contains yucca extract. It says so right on the label.

As much as 12% of extracts of the plant Yucca schidigera are soap-like compounds called saponins.

Saponins are natural detergents, or surfactants. In root beer, they make the foam. Yucca saponins have a steroid base attached to carbohydrates. This makes one end of the molecule soluble in water, and the other end soluble in fats and oils. This lets them emulsify fats and oils, so they mix with water, and helps them stabilize tiny bubbles by forming a tough film at the water/air interface.

But saponins have some other rather remarkable properties besides foam making. They are stongly attracted to cholesterol. Like some cholesterol lowering drugs, they attach to cholesterol in the intestines, and prevent it from being absorbed into the body. And since the cell membranes of many pathogens such as Giardia lamblia have cholesterol as an important component, the saponins can cause the cell membranes to rupture, killing the organism and preventing disease. They also have similar antiviral and antifungal effects, and since many cancers have more cholesterol in their cell membranes than normal cells, there appear to be anticancer benefits to yucca extract also.

The saponins are also used to aid the effectiveness of vaccines, and may have immune boosting effects.

Yucca extract contains resveratrol, the antioxidant that gives red wine its heart benefits, and antimutagenics effects.

By locking up bile acids in the intestine, yucca saponins prevent bacteria from creating cancer causing secondary bile acids and may prevent colon cancer.

Yucca extract binds to ammonia, and is used in animal feeds and kitty litter to control odors.

So drink your root beer. It’s good for you.

Herbert Benson believes in the power of prayer. He has reason to — he’s been studying it scientifically for years.

In a recent study, he and co-author Charles Bethea looked at whether there were any effects that could be traced to people undergoing surgery who had others praying for their speedy recovery without complications.

The study divided 1,800 patients into three groups. Six hundred patients were told that people were praying for them. Another six hundred were prayed for in the same way, but the patients were not informed. The last six hundred were not prayed for.

The last 600 had the fewest complications from their surgery. The group who were prayed for without the knowledge of the patients had an insignificantly higher number of complications.

The group that was aware that there was a group of people praying for them had significantly more complications. Fifty nine percent of them had complications, compared to fifty one percent in the first group, and fifty two percent in the second.

An earlier study of alcoholics who knew that people were praying for them found similar results. Those who knew people were praying for their success in sobriety ended up drinking significantly more after six months than those who thought no one was praying for them.

Richard Sloan, a professor of behavioral medicine at Columbia, thinks such studies are a waste of resources that could be better spent elsewhere. But it seems to me that the $2.4 million dollar study, funded mainly by a group that supports research into spirituality, would have been spent on some other similar study if not for this one, and would probably not have found its way into HIV or cancer research anyway. The U.S. government has spent a similar amount of money on the subject, $2.3 million dollars, and come up with similar results. Demonstrating that intercessionary prayer is ineffective, and sometimes harmful, can be of benefit to people who might otherwise be told that people are praying for them. Over a significantly long period, that $4.7 million dollars might be saved by reducing the costs of complications brought about by the activity of well-wishers with the best of intentions.

So go ahead and pray for your sick friends. Just don’t let them know.

SciFoo is an un-conference, where fascinating people gather to talk about hundreds of different topics across a wide range of fields. The talks are always interesting and educational, but the people themselves are the draw for me as much as the topics under discussion. I end up talking to very bright and usually witty conversationalists about things that none of us are expert in, and we try to solve problems from global warming to whether nitrogen gas dissolves in liquid oxygen.

Bones are made of calcium phosphate, a molecule made when phosphoric acid combines with calcium. So one would think that phosphoric acid in the diet would be good for bones.

Or maybe not. Phosphoric acid combines in the digestive system with any calcium it finds, and binds tightly to it, making the calcium unavailable to the body. Since calcium is needed in many important functions, when there is no calcium in the diet, the body gets the needed calcium from its storehouse of the mineral — the bones.

Bones are constantly being built up and torn down by cells called osteoblasts and osteoclasts. The former store calcium in the bones, and the latter mine the bones for calcium when it is needed elsewhere.

When acid levels in the diet are high, the body neutralizes the acid with calcium from the bones. This can happen when high protein diets are not supplemented with enough fruits and vegetables and other alkalinizing foods to buffer the resulting acid. The kidneys cannot excrete urine that has a pH lower than 5. The acid content of cola has a pH of 3. It would take over 8 gallons of water to dilute a can of cola down to pH of 5. Since it can’t do that, the body neutralizes the acid with calcium from the bones.

Many proteins are made of sulfur containing amino acids that produce sulfuric acid when they are metabolized. This acid needs to be buffered or neutralized before it can be excreted.

By locking up calcium before it can be absorbed, and by raising the acid levels that need to be neutralized by buffers from the bones, the phosphoric acid in cola drinks causes bone loss through two mechanisms.

Where the effects are most noticed is in children, especially adolescent girls, and women. It is not clear why men are slightly less affected by phosphoric acid in soft drinks, and the hypotheses range from hormonal activity to larger alcohol intake by men. Cola drinks have been associated with kidney stones in both men and women, however.

Mineral water is alkalinizing. Perhaps a switch to water or alkalinizing fruit and vegetable juices would be a good idea.

Not all studies blame the acid in cola. Some blame milk displacement as the primary reason soft drinks affect bone loss, and link caffeine to calcium in the urine.

Maybe switching to milk..

Dr. Robert Ross has been studying abdominal fat and mortality.

There are two components to abdominal fat. Subcutaneous fat lies just below the skin, and it is the fat you can pinch with your fingers. But it is the visceral fat, the fat located behind the abdominal muscles, that is the major risk factor in cardiovascular disease. Visceral fat is associated with insulin resistance and lipoprotein metabolism (cholesterol). People with excess visceral fat have higher triglyceride levels, and lower HDL (“good” cholesterol) levels.

Waist circumference is an accurate predictor of type 2 diabetes. Visceral fat more often accompanies left venticular enlargement and hypertension than subcutaneous fat.

Luckily, there is a method for reducing visceral fat, even without losing weight. Magnetic resonance imaging studies are showing that exercise reduces visceral fat more than other types of fat.

It makes sense that the fat deposits that correlate best with lipid metabolism and insulin levels are the fat stores used up first when exercise demands energy from fat stores.

Moderate intensity exercise (40 minute walk) increases not only aerobic capacity, but increases insulin sensitivity. You no longer get short of breath, and you are less prone to diabetes related complications.

So, all you guys with beer bellies — take a hike!

I bought six of these wonderful little radio controlled airplanes, the Air-Hog Aero Ace.

They are barely bigger than my hand, and fly for 10 minutes on a charge. Great fun, although I am a really lousy pilot, having had no time to practice. The foam body crashes into things and simply bounces back unharmed.

And they are only $30 each, complete with the radio control transmitter.

What makes them possible is lightweight lithium ion batteries (probably lithium polymer batteries, but I have not found any data on the batteries yet). With energy densities of 166 milliwatt-hours per gram these tiny batteries can power both electric motors and the radio control receiver in the plane for longer than I can keep the plane in the air (did I mention I was a lousy pilot?).

Lithium-sulfur batteries might be even better, at 280 milliwatt-hours per gram, but I haven’t seen any 5 gram lithium-sulfur batteries yet.

But batteries are not perfect. They can only be charged 500 to 1,000 times before they are no longer useful, and they take minutes to charge. What if we could have these energy densities in a capacitor? Something that could charge in a second or two, and never wear out?

Joel Schindall at MIT thinks he can raise the energy density of ultracapacitors from 3 or 4 milliwatt-hours per gram to 300 or even 400 milliwatt-hours per gram. He wants to use carbon nanotubes growing out of metal foil like fur on a scared cat.

An ultracapacitor is normally made from two metal foils covered with a fine dust made of activated carbon, in an electrolyte of acetonitrile or propylene carbonate, and separated by a porous insulator. By replacing the carbon powder with carbon nanotubes spaced just right, the porous material can hold 100 times the number of ions as the carbon can.

Of course, toy airplanes are not the only market that could use a lightweight power source that can charge in seconds and never wears out. Laptop computers, cell phones, iPods, and hybrid cars are also waiting for such a breakthrough.

Carbons like to form bonds with angles of 109 degrees, like the bonds in diamonds. It takes energy to force the bonds to form more acute angles. The highest strain energy of any organic compound available in multi-gram amounts is found in cubane, a molecule with eight carbons in a cube shape, where all of the bonds are 90 degrees.

In the early 1980’s it was pointed out that cubane’s very high density and high heat of formation would make it an especially good explosive, especially if each carbon could have a nitro group attached. The resulting molecule would decompose to eight molecules of carbon dioxide, and four molecules of nitrogen, and release a lot of heat in the process. A cubane with a nitro group on each carbon is called octanitrocubane.

Several factors are important in making a good explosive. The decomposition must be energetic. In cubane derivitives, the strain energy ensures a very energetic decomposition. The number of molecules that result should be large. One molecule of octanitrocubane becomes 12 molecules, a very good ratio for an explosive. The molecular weight of the resulting gases should be high. Carbon dioxide’s molecular weight is 44, and nitorgen’s is 28, compared to water at only 18. Explosives that contain hydrogen will have lighter resulting molecules than those that don’t, and octanitrocubane has no hydrogen.

Lastly, the density of the substance should be as high as possible. A denser explosive has a higher detonation velocity (more power), and a higher maximum detonation pressure. Octanitrocubane is the densest explosive yet.

Because it has no hydrogen, it produces no water vapor. When used as a propellant in rockets, this would mean that it would leave no vapor trail, and it would be harder to detect and track.

Some common explosives and their properties:

Octanitrocubane is up to 30% more powerful than the most powerful common military explosive, HMX. What is also important, it is very stable. It does not degrade until it sublimes at 200 degrees Celsius (392 degrees Fahrenheit). You can hit it with a hammer and it will not explode.

Perhaps fortunately, it is very difficult to make. Cubane itself is not easy, but then a 17 step process is needed to get to tetranitrocubane, and by the time we get to hexanitrocubane we are at 33 steps, then heptanitrocubane brings us to 37 steps, and finally octanitrocubane at 40 steps. Many of those steps in the reaction are quite difficult all by themselves.

Other cubane derivitives have useful properties too. They are being explored for their pharmaceutical uses, and for their unique qualities when polymerized into plastics.

When plants make oils, they prefer kinky molecules. Molecules that are straight can pack together into dense solid clumps, while kinky molecules stay liquid.

What makes the molecules kinky are cis double bonds. Most of the bonds between carbon atoms in fats and oils are single bonds, because most of the carbons are saturated with as many hydrogen atoms as they can hold, and they only have one bond left for the next carbon. Some molecules (monounsaturated fatty acids) have a double bond in them. Some (polyunsaturated fatty acids) have more than one double bond.

The carbons that share a double bond between them have only one hydrogen each. If the hydrogens are on the same side of the double bond, then the molecule kinks at the bond, forming an angle. If the hydrogens are on opposite sides, then the molecule has no kinks, and it is straight.

The organism that created the fatty acid went to some trouble to make all of the double bonds kinky (called the cis orientation, meaning “on the same side”). If we heat up the oil, we shake up the molecule, and the bonds rearrange somewhat at random, sometimes forming kinky cis bonds, but quite often forming straight trans bonds (meaning “on opposite sides”).

Trans fatty acids stack together and form solids. When they are incorporated into the cell walls in arteries, they stiffen the arteries. When they are incorporated into the myelin sheathing of nerve cells in the brain, they can cause neurodegenerative diseases. Trans fats also raise the levels of the bad form of cholesterol (LDL), and lower the levels of the good form (HDL). People who eat trans fats have nearly twice the risk of heart attack as those who avoid them.

Some 20 carbon long cis fatty acids are processed by enzymes to form prostaglandins, prostacyclins, thromboxanes and leucotrienes and other eicosanoids that the body uses to control important processes like the immune system. The trans forms of the same fatty acids don’t fit the enzymes, and can’t be made into eicosanoids.

Fully hydrogenated fats are also straight molecules, and are generally solids. Since they have no double bonds, they don’t oxidize as readily, and so they don’t go rancid as quickly as oils. They have longer shelf lives, and form the solid parts of butterfat and lard. To make similar solid fats from vegetable oils, the food industry invented hydrogenation. This is a process where the oils are heated in vessels with compressed hydrogen and some metal catalysts, to add hydrogen to the carbons at the double bonds, converting the bonds to single bonds.

Since fully saturated fats are too solid and wax-like for cooking, the hydrogenation process is not allowed to complete, so the result is a mixture of saturated and unsaturated fats. But because of the high heat used in the process, many of the cis bonds that remain have been converted to trans bonds.

A better process would be to convert all of the unsaturated fatty acids to fully saturated fats, and then to add back some unprocessed oil to thin the mixture to the right consistency. Some trans fat would still remain, since chemical reactions do not usually go fully to completion, but the levels would be much lower. However, it is cheaper to just stop the process when the consistency is right.

Tiny plankton called coccolithophores remove carbon dioxide from the air. They make little shells of calcium carbonate from CO₂ and when they die, they sink to the bottom of the ocean and make the sediments from which limestone is formed. They are also an important food source for many other creatures in the ocean, including most of what we catch and eat.

But the CO₂ that they can’t scavenge may cause them to go extinct in as little as 35 years.

What is happening is that CO₂ levels are increasing. This is making the oceans more acidic. If the oceans are not slightly alkaline, then creatures that use calcium carbonate for their shells can’t make the shells. The calcium carbonate simply dissolves in the less alkaline water.

Of course, if the coccolithophores go away, the CO₂ will build up much faster. Other creatures that make their defenses out of calcium carbonate will also go extinct, such as corals, clams, oysters, abalone, mussels — basically all of the creatures that make the seashells we collect on the beach. All gone. In our lifetime.

Animals that depend on those species will also go away. Starfish, cod, sea otters, walruses — all feed on creatures that depend on calcium carbonate to survive.

In past periods of high CO₂ levels, mass extinctions occurred, and levels of carbon dioxide only fell after mountain formation or new species evolved that sequestered carbon in the soil or in wood fibers. These are slow fixes. We won’t live long enough to see them happen.

Present levels of CO₂ are higher than at any time during the last 420,000 years, the length of time recorded in Antarctic ice cores. These cores show levels with a brief peak of 315 parts per million. Current levels are 381 ppm, and are expected to reach as high as 550 ppm by 2050.

Feedback mechanisms mean that extra carbon dioxide in the atmosphere causes heating, which causes more carbon dioxide and methane to be released from the ocean, which causes more heating.

It’s not just the heat. High carbon dioxide levels cause mass extinctions. And current levels are higher than anything in the last half million years, and getting higher at a rate of 1.2 ppm per year.

We should expect that rate to accelerate due to feedback effects.

And, of course, we continue to burn fossil fuels and put more CO₂ into the air.

Because the bathroom scale is always just sitting there, and I am a curious person, I weigh myself before going to bed, and then again in the morning. I find that I lose about 1% of my body weight by sleeping. If one third of my day is spent sleeping, and I want to lose 20 pounds, it would seem that the easiest way to do so would be to sleep for three days straight.

Eve Van Cauter has been studying sleep for a long time. While I am sure she would not recommend my sleep diet as a weight loss method, she has found that sleep regulates the levels of hormones that control appetite, and that not getting enough sleep makes people hungry.

In December of 2004, she published a study of 12 healthy young men, where she found that levels of the hunger causing hormone ghrelin increased, and levels of the hunger preventing hormone leptin decreased. The appetites of the men increased when they were allowed only 4 hours of sleep, and they especially craved calorie dense foods high in carbohydrates. When allowed 10 hours of sleep, their appetites returned to normal.

Leptin is reduced by the hormone melatonin during the night. Light prevents melatonin from being produced in the body. Artificial lighting at night reduces the amount of time that melatonin is produced, and this can reduce the leptin levels, causing hunger and cravings.

Leptin is produced in the fat cells, and tells the body how much energy is stored away. It not only regulates hunger, but it regulates the metabolism that burns energy. Low levels of leptin are associated with obesity.

It may be the beauty sleep that keeps you thin, or it may just be that you need more than 4 hours in the dark to produce enough melatonin to keep the leptin levels down. The exact number of hours of sleep (in the dark) that you need is probably higher than the 4 hours used in the study. Other studies have shown that sleep is necessary for memory, and suggest that at least 7 hours is required for full function.

Turn out the lights, and get to sleep.

Levers do it.
Pulleys do it.
Ramps, transformers, gears, megaphones, and wheelbarrows do it.
Even screws do it.

Match impedance, that is.

Impedance is the opposition to the flow of energy.

If you try to lift your refrigerator, you will experience an opposition to the flow of energy. The refrigerator will just sit there, and you will get tired. The ability of your muscles to lift the weight is not matched to the weight.

There are a number of ways you can lift a 500 pound refrigerator by matching the impedance of your muscles to the impedance of the load. You could push the load up a ramp. You could use a lever, or a block and tackle, or a hydraulic jack, or a screw jack. Each of these devices allows you to trade lifting the 500 pound load for lifting a smaller load, say 50 pounds. You generally trade off time, pushing 50 pounds for ten seconds instead of 500 pounds in one second. The same amount of energy is expended, but at a much lower power level.

When impedances are mismatched, energy put into the system is reflected back. If you jump on a see-saw with a refigerator on the other end, you will bounce back off as if you were on a diving board. But if you move the fulcrum closer to the refrigerator, you can jump onto the see-saw, and your end will move down, lifting the heavy load at the other end.

You can line up a row of billiard balls, and hit the row with the cue ball, and the last ball in the row will shoot off down the table. But if one of the balls is made of steel, the cue ball will simply bounce off of it, and most of the energy will be reflected.

We can match the impedances to get the steel ball to move. We put a row of balls in front of it, each one made of a slightly lighter weight material than the last, until the ball nearest us is almost the same mass as the cue ball. Now the speeding cue ball will stop dead when it hits the row of balls, and the steel ball will slowly move off down the table, having absorbed all of the energy.

When you shout to a friend who is underwater in a swimming pool, the sound from your voice bounces off the water, and very little sound energy gets to your friend’s ears. But take a traffic cone and put the narrow end of it into the water and shout into the large end. Now your friend can hear you, because the low pressure sound waves over a large area are converted into high pressure waves over a small area, and the water moves from the high power sound. Here we are not trading time. Instead, we are trading a large area for a smaller one.

An electrical transformer also matches impedance. It takes high voltage, low current energy, and matches it to a load the needs low voltage, high current. It also works the other way around. Without the transformer, most of the energy is reflected back to the source, and little work gets done.

A water nozzle is an impedance matcher. So is cupping your hand behind your ear.
A telescope is an impedance matcher. So is a magnifying glass, or a winding mountain road, or the gears on your bicycle.

Now that you are aware of impedance matchers, you will start to see them everywhere.

Instead, space itself expanded, allowing the matter in it to cool and condense from a hot plasma into the stars and galaxies we see today. The matter in the universe is not flying away from the center of some explosion. The matter is just sitting there, and the space it is sitting in is expanding.

Space, as far as we know, is infinite. And as far as we know, it was infinite at the time of the Big Bang. All of the matter in the universe was packed so densely that the bits that make up the farthest galaxies we can see were all within a few inches of each other a fraction of a second after the Big Bang. But there was matter packed that densely infinitely in all directions.

We can’t see all that other matter, because the light from it hasn’t reached us yet. When someone says that the universe was the size of a baseball at some moment in time, they mean that all the matter we can see was crowded into that size. Space was still infinite, and filled with an infinite amount of matter.

When we look deep into space, we see galaxies that formed billions of years ago. They are billions of light years away from us. An observer in one of those galaxies could look in the same direction we are looking, and see galaxies that we cannot see, even more billions of light years away. All of infinite space is filled with galaxies. We can only see those within 46 billion light years from us because the light from galaxies farther away has not had time to reach us yet.

Space continues to expand. Those faraway galaxies keep getting farther away. But they are not moving through space away from us. Space itself is expanding, so there is more space between us and the faraway galaxies. Because space itself is expanding, the distance between you and some distant galaxy is getting larger at a speed that exceeds the speed of light.

Matter cannot move though space at the speed of light, let alone faster than the speed of light. But because space itself is expanding, the farther away something is from us, the faster it recedes from us. At some distance, that recession speed is equal to the speed of light. Beyond that distance, the recession speed is greater than the speed of light. And infinitely far away, there are galaxies receding at an infinite speed. But they are not moving through space at that speed.

As the light from distant galaxies travels towards us, the space it travels through is continually expanding. This causes the light waves to gradually stretch. Longer waves are said to be “redder” than shorter waves, because red light has a longer wavelength than blue light. Galaxies very far away are redshifted so much that the light is no longer in the visible portion of the spectrum.

But it isn’t just light that gets stretched. All events are stretched. If a star expands and contracts on, say, a weekly basis, nearby observers will see the light from that star get brighter and dimmer every week. But an observer farther away will see the time between bright and dim phases take longer. At some distance they will see the star vary every two weeks. Farther out, it may take a month. This is because the space between the observer and the star has expanded, and the distance between the bright periods grows.

Some people refer to the redshift associated with the expansion of space as a Doppler shift. This is incorrect. A Doppler shift is what happens when a periodic signal is emitted from a source that is moving through space relative to the observer. Suppose a train was blowing its whistle as it receded from you. You would hear the sound get lower in pitch if it accelerated away from you. But if it receded at a constant velocity, the sound would keep the same pitch. If the train then stopped moving, the sound would rise back up to its original pitch.

The redshift that occurs because space is expanding does not work that way. Because the distance between peaks in the wave is getting larger as time goes by, the light gets redder as time goes by, no matter how the source of the light has moved through space in the meantime.

The difference between a Doppler red shift and the red shift due to expanding space is easiest to see when the distances are greatest. A Doppler shift of the light from a galaxy moving away from us at the speed of light would be infinite. The peaks of the wave would be an infinite distance apart. But we see galaxies receding from us at the speed of light, and the light from them is stretched by only one and a half times. We say that a galaxy with a redshift of 1.5 is receding at the speed of light. We can currently see about a thousand galaxies that have redshifts larger than 1.5, which are receding from us at speeds greater than the speed of light.

The cosmic microwave background, the light from the hot plasma of the early universe, has been stretched about a thousand-fold in the 13.6 billion years it has taken to reach us. The location in space where that light originated is receding from us at 50 times the speed of light.

The most distant objects we can see in the universe are about 46 billion light years away. The universe is only 13.6 billion years old, but because space has been expanding for that long, the distance between us and something that emitted light 13.6 billion years ago is about three times as far away as it would have been had space not been expanding.

The speed of the expansion of space is constant. This means that objects that are bound together by forces such as gravity or electromagnetic forces will stay the same size as space expands. If the expansion of space were accelerating, this would not be the case, and eventually all particles in the universe would drift apart in what has been called a “big rip”. But recent observations have shown that the rate of expansion is not increasing.

Researchers Zheng Cui and Mark Willingham, and a team of eight others, have discovered a strain of mice that are immune to cancer. When cancer cells are injected into the mice, they are destroyed. But even better, mice that have established tumors are completely cured by injections of white blood cells from the cancer resistant strain.

Highly aggressive cancers and very large tumors were eradicated when the white blood cells from the mutant mice were injected into normal mice. And the normal mice were then protected from future cancers, even normally lethal doses of injected cancer cells.

The immunity is inherited in the mutant strain, and the pattern of inheritance indicates that it is caused by a single mutation, as if a switch had been thrown to make the white blood cells super effective at killing cancers. This gives the researchers hope that a drug can be made to target that switch in humans.

The mechanism does not involve T-cells, the cells that have to be exposed to a pathogen in order to kill it. Instead, the effect is based on the innate response of macrophages, neutrophils, and natural killer cells — cells that do not need pre-exposure to the disease.

The mutation appears to have no side-effects, and does not harm the organism.

While the trait has only been seen in mice at this point, humans have an even stronger immune response than mice, because they must live longer before they can reproduce. So the effect in humans may be correspondingly higher.

I took a long walk the other day with my friend the Google Doctor, and we watched a Sceloporus occidentalis guard his territory on a sunny rock.

Commonly known as the “Bluebelly” lizard, or the Western Fence Swift, the sighting led to a discussion of a remarkable protein in the blood of the lizard, and an interesting ecological relationship between the lizard, the western black legged tick Ixodes pacificus, and the spirochete Borrelia burgdorferi, the cause of Lyme disease.

The lizard is immune to the disease. Although the tick feeds on the lizards, the protein in the lizard blood kills the spirochete.

But the effect does not stop there. The protein in the lizard blood kills the spirochetes in the tick that feeds on the lizard blood. So that tick can no longer infect other animals (deer, mice, or humans) with the disease.

In the ecology of the disease, this makes a huge difference. By cleansing the ticks of the disease, the lizards cause a dilution in the “vector space” of disease transmission, and protect a larger population of animals from infection.

The protein in the lizard blood is part of the alternative complement pathway, one of three mechanisms in the innate imune system, the fast-acting part of the immune system that can recognize thousands of pathogen molecules without being trained first by prior exposure.

An unrelated lizard, Elgaria multicarinata, the Southern Alligator lizard, also has the ability to recognize and destroy this spirochete, using the alternative complement pathway. Whether this is parallel evolution, or an indication that the disease has been around long enough to have infected their common ancestor 65 million years ago is not known.

A compass also depends on relativity to help us navigate.

Most people are aware of the strange effects of relativity, if only from exposure to science fiction. They know that time goes more slowly the faster you travel, and that rockets traveling near the speed of light appear shorter, due to an effect called Lorentz contraction. The general impression is that these effects are not significant at lower speeds. That impression is wrong.

The reason an educated person might have that impression is because of a little thing known as relativistic gamma, a function of speed that becomes larger as you approach the speed of light. Gamma tells us how much time dilation will occur, how much heavier you will get, and how much thinner you will become as you increase your speed.

At low velocities, gamma is very close to one. As the speed gets close to the speed of light, gamma gets very large:

The horizontal scale on the graph is β, the ratio of your speed to the speed of light. The curve explains why you can’t accelerate to the speed of light. If you did, gamma would go to infinity, so your mass would go to infinity, and your width would go to zero. Since it takes an infinite amount of energy to move an infinite amount of mass, you just don’t have the fuel to get there.

Gamma is usually written in one of these three ways:

As your speed v gets close to the speed of light c, the denominator gets very small, and thus gamma gets very large.

But look at the graph — until you get half the speed of light, gamma is still very close to the value one, meaning that your mass hasn’t changed much, nor has your width, or your perception of time. Half the speed of light is still 335,308,315 miles per hour. That’s really fast. At normal human speeds, such as walking, surely gamma is so close to one that we can ignore it, right?

Well, no.

It turns out that if you have something that is very small, it can be important if you have a whole lot of them. An atom might not weigh much, but an elephant is made of a lot of them. And there are a lot of electrons in a compass needle.

Magnetism seems like magic sometimes, but it is really just a whole bunch of electrons moving slowly, and showing us how relativity can happen at a walking pace.

To picture electrons moving, consider a wire connected to the terminals of a battery. The battery makes electrons in the wire move. They don’t move very fast. If there is 10 amperes of current in the wire, the electrons are moving at 0.00053686471 miles per hour. Snails go 50 times faster than that. The value of gamma for that speed is so close to the value of one that the Google calculator can’t tell the difference.

But there are 6,241,509,630,000,000,000 electrons moving past us in the wire every second. The electrons are negatively charged, moving past positively charged nuclei. Since the wire is neutral, there must be as many positive charges as negative charges.

But what happens if we walk along the wire at the speed of the electrons? The positive nuclei appear to be closer together due to gamma. A very very tiny bit closer together. The electrons are still the same distance apart to us, because we are moving at the same speed. But when we multiply a very tiny amount by a huge number of electrons, the effect of the positive charges getting bunched up together makes it appear that there are more positive charges than negative ones in the wire.

That will have an effect on any charged particle moving near the wire. The charged particle sees the wire as having a charge, but only when the particle is moving.

We call this magnetism.

It is special relativity happening at a pace that makes a snail look like a race car.

Landing in power lines and causing a 20 minute blackout in Long Beach, California, he survived rising 16,000 feet in the air (he had planned only 100), and ended his 45 minute flight alive, but was awarded an honorable mention in the 1982 Darwin Awards nonetheless.

This example of knowing just enough to be dangerous came to mind when one of my readers at Scitoys.com asked how to make a solar hot air balloon out of garbage bags that was big enough to lift one person. I answered the question anyway, since the scale of the task was big enough that this kid was unlikely to get his project off the ground.

A little hot air…

A typical hot air balloon holds 90,000 cubic feet of air and can lift 1,600 pounds.

We can assume then that to lift a 200 pound person we would need about 12,000 cubic feet of hot air.

But that air is very hot, as the typical hot air balloon is heated with a lot of propane.

In a solar balloon, where thin black plastic is heated only by the sun, we can assume there is a much lower temperature — hopefully low enough as to keep the plastic from melting. I picked 120 degrees Fahrenheit for the temperature of the air in the solar balloon, because I am an optimist.

The law that tells us just how hot air rises is called Charles’ Law. It states that the volume of a gas is proportional to the number of degrees above absolute zero the temperature is. If the outside air is 65 degrees, and the air in the balloon is 120 degrees, the air in the balloon is only 10% hotter in absolute terms.

Air at 65 degrees weighs about 0.075 pounds per cubic foot. Inside the balloon it weighs only 0.067 pounds. The difference is 0.008 pounds per cubic foot. So to lift a 200 pound person, we will need 25,000 cubic feet of hot air.

That’s a cube 30 feet on a side, or a sphere 37 feet in diameter. That’s a lot of garbage bag.

On a lighter note…

In 1814, Amedeo Avogadro published a scientific paper where he explained that the number of molecules in a volume of gas is a constant. So if we want to make a volume of gas lighter, we should choose a lighter molecule.

Hydrogen is the lightest element. An atom of hydrogen weighs about 1 atomic mass unit, since it is little more than a single proton plus one tiny electron. There are two atoms of hydrogen in a hydrogen molecule, so the weight is about 2 amu.

Air is made up mainly of three parts nitrogen molecules and one part oxygen molecules. Nitrogen weighs about 28 amu, and oxygen about 32. So air is about 29. That’s about 14 times heavier than hydrogen.

To lift a 200 pound person, you would need a spherical bag of hydrogen about 18 feet across.

At this point you might have pictures in your head of flaming dirigibles crashing into New Jersey, and be thinking that helium might be a better gas to use. Helium is pretty good. An atom of helium weighs about 4 amu (it has two protons and two neutrons). And, helium doesn’t combine well with other elements, or even itself, so each “molecule” of helium is just one atom. So even though a cubic foot of helium weighs twice as much as one of hydrogen, it still weighs 7 times less than air. And, since the volume of the sphere goes up as the cube of the diameter, lifting a 200 pound person still takes less than a 19 foot radius bag.

Other gases

There are other gases we could use. Pure nitrogen is lighter than air, by a little bit. Methane only weighs 16 amu, so it is about half the weight of air. Ammonia is 17 amu, and neon is 20.

I sometimes ask kids to guess which is heavier — humid air, or dry air. The natural guess is humid air. After all, water is heavy, right? Water vapor weighs 18 amu — only a little heavier than methane. Displacing heavy air with light water vapor makes a lighter mixture, not a heavier one. Pilots of airplanes sometimes need to take the humidity into account when they calculate how much the plane can lift.

Of course, to keep the water from condensing on the inside of the balloon, we would need to keep the temperature above boiling, which would add even more to our lift.

Martin brought up the ideas of his mentor, Fred Hoyle, on the subject of panspermia, mentioning that since Hoyle believed in the Steady State Theory as opposed to the Big Bang, there was much more time for panspermia to happen.

Time is an important factor in the question of whether life originated on Earth or in space. With enough time, life could spread around the universe, and end up being quite common. Whether life is common has other implications relating to the question at hand, however. If life commonly evolves whenever the conditions are right, then it probably evolved on Earth, perhaps many times (this is in fact the subject of one of the talks at SciFoo).

If life is very common, then it may have arrived from space many times, as well as evolving on Earth many times. But do we have any evidence that life is that common? We have been to the moon and Mars looking for life, and so far no place we have looked in the solar system seems to have as much life as the Earth does. Of all the places in the solar system to expect life to have evolved, the Earth looks to be the most likely.

We don’t yet have the technology to look for life on other solar systems to see if it is common. And so far, we have not heard from any extraterrestrial civilizations. So what are the chances of life arriving from outside the solar system if life is not inevitable whenever the conditions are right? What if life is rare?

As we look farther out into space, the odds of finding an earthlike planet go up as the cube of the distance from Earth. The time it would take life to get to Earth from another planet only go up linearly with distance. So if bacteria inside a chunk of rock blasted away from a planet by a meteorite could live forever in space, the odds of life reaching Earth don’t look so bad, if we look far enough out.

This is where having infinite space and infinite time to travel helps. But in a Big Bang universe, we only have 13.73 billion years to play with, minus the 4 billion years life has been on Earth. So how far could life have travelled in 10 billion years?

The fastest meteors travel about 160,000 miles per hour. Whether life in such a meteor could survive hitting the atmosphere is questionable, but we will use that number. Travelling at that speed for 10 billion years, a meteor could travel 2.3 million light years. That’s about as close as the Andromeda galaxy, one of the closest to the Milky Way. So we should probably assume that no life would have come from outside our own galaxy.

There are about a hundred billion stars in the Milky Way. Perhaps 10% of those are stable enough, far enough away from supernovae, and have enough heavy elements to support life. If 30% of them have planets, we have 3 billion places where life might have evolved. That’s a big number, but we still have to get life off of that planet, and onto Earth. What are the odds that an asteroid would hit a planet with life, blast a rock from it, and that rock would then hit Earth? Space is pretty big.

All of this still presumes that life can last billions of years inside a meteor travelling through space. Suppose there are 100 trillion cells inside the meteor (I have about that many in me). If half of them die each year, there won’t be any left in a thousand years. If somehow the life in the meteor could live for a million years in space, it could only travel 238 light years before it died. That narrows down the number of stars that could contribute to life on Earth.

There are about 200 stars within 25 light years of Earth. Within 250 light years, we should expect about 200,000 stars. If we stick with 3% of those being suitable for life, we have 6,000 places where life could evolve and survive being blasted to Earth. I would bet that the odds of a meteor taking life from one of those places to Earth are less than 6,000 to one.

Thus it seems to me that it is more likely that life evolved here on Earth than that it came from outer space.

I had lunch yesterday with Steven Benner.

The last time we talked had been in August of 2007, and the discussion centered around his work in synthetic biology — creating DNA strands with 12 nucleotides instead of 4, and proteins with more than 20 amino acids.

This time, he was here for the Astrobiology Science Conference to talk about life on other planets. But he took the time to visit Google to talk about his recent project, generating tools and techniques to cheaply and quickly find the genetic differences between a patient and a “reference genome”, such as the one generated by the Human Genome Project.

By pulling out only the differences between two people, this approach can dramatically shorten the time needed to sequence a person’s DNA, and reduce the cost accordingly. He estimates he can show how your DNA differs from Craig Venter’s DNA for about $35,000. Since we know Venter’s DNA from the Human Genome Project, knowing the differences gives us a complete picture of your DNA.

The talk intertwined with several of his other research interests, touching on his work using synthetic DNA to make diagnostic tests for HIV and hepatitis, his explorations into structural biology and experimental paleogenetics, and bioinformatics.

At lunch after the talk, the discussion ranged even more widely, as we toyed with solutions to problems of drug regulation, drug resistance in microbes, paleolithic diets, global warming, and species extinctions.

This is definitely someone I will want to talk to again — there seemed to be new ideas in every sentence.

At first I thought it was a common European Brown Snail that was somehow bleached white or covered with some kind of salt deposit. Shoreline Park is, after all, at the shore. But after close examination I became convinced that this was a different type of critter altogether. It was naturally whiter than the snails I was used to seeing farther inland, and seemed a bit flatter (less pointed), and inside, it had a dark stain on the shell.

After some searching on the web, I tentatively identified it as possibly a Milk Snail (Otala lactea). Readers who view the photos and have a positive identification are eagerly invited to send me email or comment on this article.

But as most web searches do, this one led to more questions, and more browsing. Many sources mentioned the introduction of the European Brown Snail (Cantareus aspersus) to California by a Frenchman in or around 1850. Others disagreed, or had variously different versions of the story. But nowhere could I find information on who the Frenchman was, or a definitive source for the story.

I often ask my friends at Google for examples of things that are difficult to find using a web search. This has become something of a game. So here was one example staring me in the face. Who started the story about the Frenchman importing escargot to California, only to end up dumping them into a river?

The story seems to be one of those where you can tell it is suffering from “telephone game” distortions after being told too many times. Once source claims the snails were dumped in the Santa Clara River in Northern California. But that river is in Southern California. Another source claims that if San Franciscans wouldn’t eat them, he concluded no one would. Another says the market for snails during the Gold Rush was “too unsophisticated” to eat common garden pests.

One reference in Google Books cites an author Forbes writing in 1850, and another, Stearns, writing in 1900. It is this last reference where I hit pay dirt.

Robert Edwards Carter Stearns (1827-1909) tells of a Mr. A. Delmas, of San Jose, California, who brought a stock of European Brown snails to a vineyard on the west bank of the Guadalupe river in the Santa Clara valley (what we now call “Silicon Valley”). Stearns notes that the valley was settled by “a few French families”, and that the introduction of the snail was ‘with an eye to the pot’. By 1900, the snails had crossed the river to the east side, and were becoming a nuisance in gardens.

The snails were also planted in San Francisco and Los Angeles by the elder Mr. Delmas, but Stearns could not find any in San Francisco, concluding that the weather and drifting sands in that city in 1860 would be inhospitable. Things had changed by 1900, and he thought they would “find a congenial environment in Golden Gate Park” if they were ever brought there. They were already a problem in Oakland at that time, and in Elysian Park in Los Angeles.

It is now about 150 years after Mr. Delmas released the critters in San Jose. There seem to be few places I have visited in California where they are not a common garden pest, if you live in a city. Where I live, a few miles away from San Jose, they are absent — I live on a mountain, surrounded by steep dry hills. But in the houses at the base of the mountain, a constant battle between mollusc and man goes on.

Some of the attendees I had met before, or even known well, such as Theo Gray, Chris Dibona, Sergey Brin, Peter Murray-Rust, Dean Kamen, Josh Bloch, Tim Hubbard, Vinod Khosla, and Larry Page, but most others were people I had only read, or read about.

The photo above shows Freeman Dyson, Sir Martin Rees, and Jaron Lanier. More photos here.

Steve Benner led or spoke at several marvelous discussions about synthetic biology and issues relating to recombinant DNA research and biohacking, along with Roger Brent (who had some interesting applications for the ultraviolet LEDs I was handing out).

Henry Gee led a discussion on science fiction, attended by Kim Stanley Robinson, Neal Stephenson, and Greg Bear, during which we found that many of the scientists in the audience were also writers of science fiction.

If you see people in the photos wearing light sticks from scitoys.com, that’s because I brought a few hundred of them and passed them around. People got very creative with them.

Charles Simonyi talked about his recent tourist visit to the International Space Station, and Martha Stewart stood up during his talk to tell us about making meals for him to take up into space.

And I finally got to thank Martha Stewart in person for getting my company off to a big start — a large order of my Film Can Cannons helped “start her company off with a bang” at the IPO party for MSLO, and was the first big order for scitoys.com.

Eric Drexler, Lee Smolin and Freeman Dyson play with light sticks from scitoys.com.

A friend of mine suggested at lunch that the money spent on the war in Iraq might buy a lot of solar panels.

So how many solar panels would $307 billion (at the time of this writing) buy?

My 5 kilowatt system, installed, with inverters and mounting, cost about $50,000 before government rebates. At that cost, we get 6,145,956 houses powered by solar energy. And another house gets solar for every 50 seconds the war continues (call it a house per minute).

The rule of thumb is that a house gets 6 hours a day of usable sun, so 6,145,956 * 5 kilowatts * 6 hours is 184,378,680 kilowatt hours per day.

Prior to Iraq’s invasion of Kuwait, Iraq was producing 3.5 million barrels of oil per day. In December of 2002, the U.S. imported 11.3 million barrels of oil from Iraq.

One barrel of crude oil is equal to about 1700 kilowatt hours of electricity. So Iraq was producing the equivalent of about 6 billion kilowatt hours per day. The U.S. was importing the equivalent of 620 million kilowatt hours from Iraq per day.

So, if we built solar panels with the money, we would get more than a third of the energy that Iraq supplied per day, but from the sun instead of from oil. If we continued to spend at that rate for another two wars worth of time, we would more than break even.

Now this is assuming that there are no economies of scale to be had from spending $307 billion on putting up solar panels. If there were only a factor of 3.37 in our favor, we could have effectively bought the energy equivalent of all the oil in Iraq for the cost of one war.

And, yes, the efficiency of producing electricity from oil is not 100%, (more like 40%), and there are transmission losses in the grid that you don’t have when each house is producing its own electricity, so we get our factor of 3 right there.

Joseph Stiglitz (former chief economist at the World Bank) estimates that the cost of the war on the U.S. economy is between $1 trillion and $2 trillion. Now those solar panels are looking really cheap.

So don’t blame the president’s decision to invade Iraq on the need for oil. He’d have to be stupid to have done that.

When airline passengers were told on August 10th, 2006, that they could no longer bring liquids aboard airplanes, the fear was liquid explosives.

Most people can probably name one liquid explosive — nitroglycerine, or more properly glyceryl trinitrate, or propane-1,2,3-triyl trinitrate. Ramzi Yousef used contact lens solution bottles filled with glyceryl trinitrate to blow up a Boeing 747 going from Manila to Japan.

But while glyceryl trinitrate is known for its dangerous instability and ease of detonation, the news reports were mentioning an even less stable chemical, triacetone triperoxide. This chemical can be detonated by a flame or by friction, but it is a solid, not a liquid. The reporters may have been confusing it with methyl ethyl ketone peroxide, which is a liquid made in basically the same way, but starting with a different organic solvent. Or they may have simply been assuming that the explosive rumored to have been used the previous July 7th was again being considered.

The news reports went on to give recipes for making TATP from hair bleach and acetone. The recipes are widely available on the web, but following the typo-laden instructions is more likely to lead to a premature death or dismemberment than a useful and transportable device. Substances that are used because they are less stable and easier to set off than military explosives are not something for amateurs to cook up from recipes on the Internet.

The drag racing fuel nitromethane can be sensitized with alkalies to become more easily detonated. Nitroethane is another liquid that can be coaxed to explode. The explosive dithekite has also been mentioned, but none of these is as easy to make in a kitchen as TATP, and none are as easy to detonate.

Methyl nitrate is another, but it has an odor that would cause suspicion (and headaches). Another liquid mentioned in the news reports is Fixor, whose web page mentions that it can be carried aboard passenger airplanes (not anymore, I suspect!).

The reason for using liquid explosives is that the X-ray machines and other devices for detecting explosives rely on density and other properties of solid explosives, and liquids explosives look like innocuous ordinary liquids to them. I suspect that peroxide explosives might have passed through sniffer detectors that were designed to detect nitrate based chemicals, but newer detectors are sure to catch them.

Yesterday I had lunch with Harold McGee. He is the author of the classic book on the chemistry of cooking, titled “On Food and Cooking”. Lunch was great — we ate with the head of Google’s many cafes, and with the chef, the Google doctor, the Google nutritionist, and some special guests.

The conversation was about food, chemistry, writing, the ten years of writing and research that culminated in the book, the new second edition, book tours, book signings, abalone (the chef had prepared a special plate of delicacies), and teaching. I’m sure I left something out.

Long after lunch, I was walking past a lounge area and heard my name shouted. Harold was sitting on a couch in conversation, having finished his tour of the Google campus, but apparently not yet ready to leave, even though it was approaching 3 in the afternoon.

I joined him, and the talk turned to web sites.

He has a very pretty website http://curiouscook.com, with biographical information and excerpts from the books, but not a huge pile of content. But he has collected a book’s worth of miscellaneous gems of knowledge about food and cooking that just didn’t fit into any nice categories. Besides, On Food and Cooking was already 896 pages long.

The answer, of course, was to publish this information on the web site, where it will be a magnet for visitors interested in cooking, chemistry, food, and how they all fit together. We discussed some ways to organize and present it, and to get the work into the right form. We talked for over an hour, and I was almost late for my next meeting.

So, keep an eye on his web site — there is likely to be a flood of fascinating new information coming soon.

Yesterday I went to the Maker Faire in San Mateo. The publishers of Make magazine pulled together a whole bunch of gadgeteers and inventors to show off their projects at the fairgrounds.

There were propane flame cannons booming away, plug-in Prius conversions, and a supercomputer built from recycled PCs.

Yahoo! had a large booth, and the Wondermagnets booth was demonstrating my Gauss Rifle.

I met several people I know there. Marius Milner, author of NetStumbler was there with two kids, and while we were chatting my old friend Brad Templeton astonished my wife by remembering her name (we all worked together in 1980 at the company that became VisiCorp). And I finally got to meet Bill Gurstelle, author of Backyard Ballistics, who reviewed my book Gonzo Gizmos, and is quoted on the back cover. He was demonstrating how to build a spud gun.

There were lots of remote controlled battle bots, showing their scars from competition, lots of computer projects, autonomous robots, and electric cars like the Xebra. There was a big black bus in one of the exhibit halls, and people were encouraged to build little LED lights with magnets on them, and throw them at the bus as an art piece. There was even a band playing, trying to be heard over the roar of propane cannons, the whine of computer controlled routing machines carving wooden artwork, and vegetable-oil fueled generators for the supercomputer built from scrap.

And all throughout the huge fair, kids were building gadgets, or playing with armfulls of helium foam. Definitely an event not to miss.

Yesterday I got to ride in Ian Wright’s electric supercar, the Wrightspeed X1. In 3 seconds, we went from stopped to 60 miles per hour, and kept accelerating. By the time 8 seconds had gone by, we were moving at over 100 miles per hour. My stomach tightened, my fingers gripped the tubular steel frame for dear life, and we kept accelerating at nearly a full G. Finally, we slowed down, turned around, and the whole terrifying ride started again.

It isn’t the speed that terrifies you. It is how fast you get to that speed. Your brain doesn’t have time to get used to it. The X1 is better than any rollercoaster ride for getting the adrenalin going.

The car runs on $40,000 worth of Lithium Polymer batteries. Driving in a sane manner, it will go for 125 miles on a charge. But nobody buys a car like this to drive sanely. But it will do 100 of those quarter mile races before needing to be plugged in. That’s a lot of adrenalin.

Ian Wright did the driving, and he built this prototype by hand for about $150,000. But he calculates he can make money selling production versions for $100,000 each.

Yesterday the folks from Space Island came to Google to give a presentation. These folks are raising money to build space stations, using shuttle external fuel tanks. They plan to rent space in the stations to manufacturers, researchers, and tourists, and to build solar power satellites, and other orbital construction.

The presentations were much too slick for the tech-heavy Google crowd, making the project seem more like Disneyland meets Las Vegas than a serious space program, but the question-and-answer period quickly got down to hard science and economics as people asked about safety issues, solid rocket booster exhaust, timeframes, and costs. There were good answers for all of the questions, and if they can actually raise the $5-7 billion they want, it looks like they can probably do it, and maybe even make money at it.

Some parts of the plan were less convincing than others. Snagging near earth asteroids for building material sounds like something I wouldn’t want to bet a company on. But that was not presented as a necessary part of the business plan, just something that would be a nice benefit later. The weather control ideas sound a little dangerous. The Mars mission is a long shot. The economics of solar power satellites have interested China and India, where getting power to rural locations is difficult and expensive. But where access to the grid is available, ground based solar arrays might be more economically sound, even though they only produce power 8 hours out of 24 on clear days. It seemed to some in the audience that putting up a lightweight mirror would be cheaper, and putting the heavy solar panels in Arizona or central Australia where clouds are not an issue would make more sense.

Their schedule is certainly intriguing. They hope to have the first modules in space in five years or less.

Al Gore came to Google today, and gave a very slick and well presented talk about Global Warming, presenting in a neat package what is known and accepted by scientists about the subject, and what needs to be done right away. This talk is the basis for a documentary about the subject, coming out next month.

Part of the talk concerned the Meridional Overturning Circulation (MOC) in the oceans, also called the Thermo-Haline Circulation, or the global conveyor belt. The MOC is the system of warm and cold ocean currents that redistribute heat from the tropics to the poles, and is the reason why Europe has a mild climate despite being the same latitude as Alaska. Part of the worry about global warming is that this current might shut down, making Europe much colder and the tropics hotter. Hotter tropics mean more and stronger hurricanes. Colder Europe means France might have the weather that North Dakota has, and similar wine production.

So it was particularly interesting when I returned home and opened this month’s Physics Today, which reports that the MOC has slowed by 30% since 1957.

As global temperatures rise, the warm water currents become warmer. This makes them more buoyant, and they don’t cool and sink as easily when they reach the poles. Added to this is that warm water evaporates faster, and warm air holds more moisture, so there is more water in the air to fall as rain when it reaches the cooler northern latitudes. This extra rainfall dilutes the salt water at high latitudes, making it lighter and less inclined to sink. In June of 2005, Ruth Curry predicted that the extra rainfall would take 100 years to stop the Gulf Stream, unless meltwater from the Greenland Ice Sheet sped up the process. She did not have the recent data showing the 30% change in the current in the last 50 years, or the recent data on the speed of melting of the Greenland glaciers. But I suspect Europe might be a little worried even if it does take until 2105 for the Gulf Stream to shut down.

Their children might live long enough to freeze there. Europe is the same latitude as Mongolia, after all. And a good bottle of Mongolian red wine is hard to come by.

Nobel laureate James Watson, who discovered the structure of DNA with Francis Crick in 1953, came to Google to talk to us about his current work on the genetic basis of autism.

He talked first about the events of 50 years ago, a talk he had previously given to the Commonwealth Club.

He then talked about his work at the Cold Spring Harbor Laboratory on autism and genetics. He didn’t mention the recent discovery by UCLA scientists pinpointing an autism related region on chromosome 17, but he did talk about regions on chromosome 15, and several times referred to the work of Simon Baron-Cohen on fetal testosterone.

Since males have a much higher risk of autism than females, and fetal testosterone may be involved, much of the talk and even more of the questions at the end of the talk dealt with Watson’s ideas about mental differences between the sexes. He linked mathematical ability to masculinity, and said that mathematically inclined men “should marry for beauty”, since there is a higher incidence of autism in children where both parents have “masculine” traits like mathematical ability. He said he thought Rosalind Franklin may have been a high intelligence autistic, and that explained why she did not deal well with potential collaborators. He said that ex-Harvard president Laurence Summers’ comments about why fewer women become professional scientists or engineers was right, and that Summers’ only mistake was apologizing.

This unabashed lack of political correctness got a mixed reception at Google, which has a large and growing number of respected and brilliant women scientists and engineers. While the data was not questioned, the conclusions drawn came up for discussion several times during the short question and answer period that followed the talk.

Watson also talked briefly about his involvement with the Human Genome project, and Craig Venter’s shotgun approach to sequencing, which won out over the approach Watson and others originally planned for the project. He said that they had thought the shotgun approach would not be able to handle the large areas of repeats in the code, but that recent advances in computer software and hardware is making that problem less of an issue.

All in all, a surprisingly eye-opening look at a scientific icon.

Vinod Khosla came to talk to us about his latest venture — solving the energy crisis and getting the U.S. off of our addiction to fossil fuels.

He was introduced by Eric Schmidt, and Larry Page, with Sergey Brin in the back of the room. He and Richard Branson are both investing large amounts of money in similar projects. What these five billionaires are getting excited about is ethanol.

Moonshine in the tank. Flex Fuel Vehicles running on E85 (gasohol) or straight hooch.

There is a long history in the U.S. of subsidizing ethanol production from corn for use in vehicles. But corn is not the most efficient base to start from — it takes one unit of energy to get 1.5 units back in the form of ethanol. But science is coming to the rescue, and new technologies are making ethanol far more efficiently, and from non-food sources, such as fast-growing switchgrass and miscanthus prairie grasses. These new technologies produce 8 times the energy they use as input.

Some of his talking points were:

• Many cars and trucks are already Flex Fuel powered, and will run on E85.
• Five million U.S. vehicles are already Flex Fuel vehicles.
• 70% of the vehicles in Brazil have ethanol in the tank.
• Brazil is saving $50 billion annually in oil import costs.
• Ethanol is already cheaper than gasoline, without subsidies, per mile driven.
• It costs $40 to make a car into a Flex Fuel vehicle.
• It would take between 55 million and 114 million acres to fuel America.
• The state of South Dakota could produce enough ethanol to be the third largest energy exporter after Saudi Arabia and Iran.
• Farmers can make more money growing ethanol feedstock biomass than corn and soybeans.
• Biofuels are carbon neutral.
• The technology in this area is developing rapidly.

So, why aren’t all those 5 million Flex Fuel vehicles running on ethanol? Because the corner gas station doesn’t have an E85 or ethanol pump. Khosla suggests that Walmart should set up such pumps at every store. After all, they want people to drive to Walmart, and the product is cheaper than gasoline, both per gallon and per mile. And it is environmentally friendly. And E85 gives cars more horsepower and longer range between fillups.

Khosla would like to see two main changes to legislation:

• Require 70% of new cars to be Flex Fuel. GM may do this even without regulations.
• Require E85 pumps at 10% of all gas stations.

A third legislative change is designed to thwart price manipulation by oil producing countries: if oil drops below $40 a barrel, the government should buy it and stockpile it for when the price goes up again. That would stabilize world prices, and prevent the oil producers from quashing ethanol economies by temporarily removing the incentives.

The economics say this will all happen in 30 years or less, all by itself. But Khosla thinks it can be done in 5 years by a concerted effort, and people will get rich doing it.

This is the cheapest way to get solar power into cars. We can get off the oil input habit, and become a net energy exporter. We have what it takes.

Al Gore is coming to where I work to talk about Global Warming.

He will likely discuss human sources of greenhouse gases, such as carbon dioxide from fossil fuels, and unburned methane from petroleum production.

But he might also mention the emissions from livestock.

Now while you might expect the job of measuring these emissions would involve close study of the south end of northbound animals, it turns out that most methane emissions from cattle happen at the other end.

About one third of the 10.2 million tons of methane produced by agriculture in the European Union is produced by livestock manure, while the rest comes from belching bovines, sheep, and pigs.

On the way to becoming meadow muffins, all that grass is feeding lots of bacteria in the digestive systems of ruminants, and they convert it into methane.

Methane production is far lower in volume that carbon dioxide production, but methane is a more effective greenhouse gas, making it’s production a concern.

The search for ruminant diets that reduce methane is not just driven by concerns about global warming. All the energy in the methane is lost to poor Bossy, who could use it to produce more milk.

So the farmers are interested in better foods to boost production. Of milk, that is, not cow flatulence.

The news has been full of reports recently about health problems related to Vioxx, Bextra, Celebrex, and other cox-2 inhibitor pain killers. Personal injury lawyers are putting up ads all over the place to drum up business. Do a Google search for any three of those names and the page will be full of lawyers advertising for clients.

So what is all the fuss really about?

These drugs are nonsteroidal anti-inflammatory drugs, or NSAIDS. NSAIDS include Bextra, Mobic, Ibuprofen, Daypro, Naprosyn, Celebrex, and Vioxx, and aspirin. Over 50 different NSAIDS are currently available in the U.S.

Aspirin, of course, has been used for years for headaches, arthritis, general pain relief, and fever reducing. But aspirin can cause bleeding in the digestive system. When Vioxx was invented, it was marketed as an alternative that was safer. Then Celebrex and Bextra came along, but they turned out to be no safer than aspirin for the stomach.

The new drugs target an enzyme called cyclooxygenase-2, more commonly abreviated as COX-2. The hormone prostaglandin is a major regulator of pain and inflammation. It is produced in the body from the omega-6 fatty acid arachidonic acid. Enzymes convert arachidonic acid into prostaglandins, thromboxanes, prostacyclin and leukotrienes, all important bioactive substances. The enzymes that do this include cyclooxygenase, lipoxygenase, and peroxidase.

NSAIDs generally work by inhibiting cyclooxygenase. The problem is that there are several prostaglandins that are inhibited, not just the ones that regulate fever and pain. The prostaglandins that are responsible for the protective mucus lining in the stomach and intestines are made using one form of cyclooxygenase (COX-1), and the prostaglandins that are responsible for pain and inflammation are made using another form (COX-2).

So, pharmaceutical companies set out to make substances that would inhibit COX-2 without interfering with COX-1, so there would be less damage to the protective mucosal lining in the gut. Vioxx came along, and was followed by 50 others. People got rich.

Aspirin is also known to have protective effects against heart disease, through a number of mechanisms, one of which is reducing inflammation. In studies on the new COX-2 pain killers, when comparing them to Naproxen sodium (Naprosyn), it was found that Naprosyn had fewer bad effects on the heart than the newer drugs. At first this was attributed to Naprosyn having aspirin-like protective qualities for heart disease. But after more study, it came out that some of the new COX-2 inhibitors were actually causing problems.

That’s when regulators and lawyers came in, followed by news reporters, and more lawyers.

So now you know.

I got a chance to talk to John Morgan today about an experiment he ran at the Haas School of Business at UC Berkeley.

His experiment set out to see if there was a benefit to sellers to switch between eBay and Yahoo! auction sites. Among several interesting points, it came out that sellers could make 29.7% more money on eBay for the same items, with the same descriptions, from the same seller with the same reputation.

One of his conclusions is that eBay is becoming a monopoly, and this is evidence of “tipping” towards that state.

So I asked the question — If someone can buy things at Yahoo! and sell those things on eBay and make an immediate 30% profit, why aren’t there arbitragers making money that way, and flattening out the markets? The answer was that the information was not widely known, and so the arbitragers weren’t there yet.

The next question was — Wouldn’t it be in Yahoo!’s best interest to make this widely known, so that the tipping towards an eBay monopoly would be thwarted, and Yahoo! would make more money, and the end users would benefit from competition?

Of course Dr. Morgan could not speak for Yahoo!, but seemed to agree that it would be in their interest to make his work a best seller.

So, all of you auction site site users, and all of you who are quick with the occasional Python script, do yourself and Yahoo! and possibly the world a favor, and help stamp out a burgeoning monopoly, and get a 30% return on investment right away.

Now that even the last holdouts are admitting that global warming is real, and is largely the result of human activity, we can look at the effects of climate change on human activity.

Much of the concern has rightly been about losing coastal areas where most of the human activity takes place, or would like to. The effects on food production, weather, and biodiversity have gotten much attention.

But what caught my attention recently was something of less economic impact, but disturbing nonetheless. A synergistic combination of increasing jet aircraft contrails and global warming. each increasing the other, will increase cloud cover so much by 2050 that earth based telescopes will become useless.

People around the globe are working hard to build extremely large telescopes of over 100 meters in diameter. But all that work may have a short-lived benefit if the telescopes can’t see through the clouds a decade or two after they are built.

The sunshine vitamin is Vitamin D.

Vitamin D comes in several forms. One of them is a steroid hormone known as Calcitriol or less commonly by its cute nickname 9,10-seco(5Z,7E)-5,7,10(19)-cholestatriene-1a,3 b ,25-triol.

Your skin contains a substance called 7-dehydrocholesterol. Ultraviolet light from the sun converts this into Vitamin D₃, also known as cholecalciferol.

Cholecalciferol is brought by the blood to the liver, where is it converted into the cleverly named 25-hydroxyvitamin D 3 [25-(OH)D 3 ] by a liver enzyme. This is brought to the kidneys by the bloodstream, where it is converted into calcitriol by the kidney mitochondia.

Vitamin D is most famous for its action in the intestines, where it is essential for the absorption of calcium, making the mineral available to form bones. The lack of Vitamin D causes the bone disease rickets.

But what has caught my attention is the lesser-known effects of Vitamin D on cancers, such as colorectal cancer, prostate cancer, breast cancer, ovarian cancer, non-melanoma skin cancer, and malignant melanoma. These last two in interesting, since the same ultraviolet light from the sun that creates Vitamin D also causes skin cancer. But occupations that give workers more sunlight seem to protect agains all of these cancers, especially breast and colon cancers.

So, people who are slathering on sunblock and avoiding sun exposure to prevent skin cancer are also eliminating a source of a substance known to help fight cancer. The good news is that various forms of Vitamin D are available in dairy products and vitamin supplements.

And guess what the two most common forms of cancer are in the United States? Skin cancer, and prostate cancer.

Drink your milk folks. And a vitamin pill might also help.

Two of them are particularly interesting to me at the moment. They are GDNF and BDNF. What interests me about them today is that they are produced in the body as a result of exercise, such as walking for an hour a day.

The effects of BDNF and exercise are an increase in brain cells, and an increase in the branching of the brain cells that contribute to brain function and memory.

One researcher, Carl Cotman, refers to BDNF as “brain fertilizer”. Rats and mice that are allowed to exercise as much as they like perform much better on memory tests than sedentary rats and mice, and their brains show much higher levels of connectivity.

The other protein, GDNF, protects brains from Parkinson’s disease, Alzheimer’s disease, and Amyotrophic Lateral Sclerosis (ALS).

So why am I interested in these proteins today? Thursday is the day of the Google Weekly Walk. A bunch of us Googlers meet in the building 42 lobby at 3:00 pm, and then take an hour long walk around the lake by the golf course.

It’s a beautiful walk by the stream and the little lake, and you get to talk to very smart people about just about anything, people who you might not otherwise have any occasion to talk to.

And you build a better brain at the same time…

There is a hormone called ghrelin that is produced in the lining of the stomach when it is empty. This hormone travels through the blood into the brain, where it triggers receptors in the hypothalamus to make you feel hungry.

If you feel hungry, it is a good bet that there is ghrelin getting to your brain.

The hormone has that funny name because it regulates the release of growth hormone. (Growth Hormone RELease, folowed by the “in” suffix used for hormones.)

While the benefits of human growth hormone are well known to athletes and geriatricians, the effects of ghrelin in the brain are what I am interested in at the moment, because they seem to reach beyond the appetite stimulus, and affect learning and memory.

I go on a low calorie diet every February, and one of the things I have noticed during those periods (beside feeling hungry all the time) is that I seem to be more alert, and paradoxically feel like I am full of energy. It now seems that these mental benefits are more than just delusions of a starving brain.

Now, there also seems to be evidence that hunger might also increase anxiety and aggression, although I have not noticed those effects while on my diet. But if you do, there is a quick cure in the refrigerator.

Just don’t eat yourself stupid.